1. Field of the Invention
The present invention relates to a technology for preventing illegal use of recording media that can be used instead of cash.
2. Description of the Related Art
It has become common to set slot machines having a function of issuing a ticket with a barcode printed thereon (hereinafter, “ticket”) in amusement shops or gambling shops such as casinos. A player inserts cash in the slot machine and can play games within the amount of the cash. When the player stops playing or hopes liquidation, he presses a dedicated button on the slot machine so that the slot machine ejects a ticket with a value corresponding to the remaining amount assigned thereto.
The player can use the ticket on another slot machine or use the ticket on some other day and play games within the remaining amount. When the player wants to liquidate the ticket, he:                (1) inserts the ticket in a ticket liquidation machine (Refer to U.S. Pat. No. 6,048,269),        (2) carries the ticket to a cashier counter and request a person in charge of the cashier counter (hereinafter, “cashier”) for liquidation of the ticket, or        (3) carries the ticket to a person responsible for pouch pay (hereinafter, “pouch payer”) and request the pouch payer for liquidation of the ticket.        
FIG. 1 is a schematic of conventional a ticket manage system provided in a casino. A plurality of slot machines 10 are set in the casino and players can play games by inserting cash, such as coins and/or bills, into the slot machines 10. Each slot machine 10 is provided with a liquidation button. When the player presses the liquidation button, the slot machine 10 dispenses a ticket 20 with a value corresponding to remaining amount.
Information concerning the ticket 20 is managed in a ticket management database 50 in a server 40. More specifically, the ticket management database 50 stores therein information such as a ticket ID, a ticket state, and a remaining amount for each ticket output by the slot machines 10. In the example shown in FIG. 1, the ticket state of “unprocessed” for the ticket ID 1111 indicates that the corresponding ticket has not been subjected to liquidation, while the ticket state of “processed” for the ticket ID 1112 indicates that the corresponding ticket has been subjected to liquidation.
When liquidating the ticket 20, the player inserts the ticket 20 into a ticket liquidation machine 60 and performs a prespecified liquidating operation. As a result, the ticket liquidation machine 60 dispenses cash equivalent to the amount in the ticket 20. The player can also liquidate the ticket 20 by carrying the ticket 20 to a cashier counter and requesting the cashier for liquidation. As a result, the cashier pays back cash equivalent to the amount in the ticket 20. The player can also liquidate the ticket 20 by carrying the ticket 20 to a pouch payer and requesting the pouch payer for liquidation. As a result, the pouch payer pays back cash equivalent to the amount in the ticket 20.
The cashier uses a cashier terminal 70, or the pouch payer uses a pouch pay terminal 80 to send information such as the ticket ID to the server 40 and receive information such as the amount remaining in the ticket 20 from the server 40. When the liquidation process is over, the cashier terminal 70 or the pouch pay terminal 80 sends a notice that indicates that the liquidation complete to the server 40. As a result, the ticket state of the ticket 20 in the ticket management database 50 is changed to “processed”.
As described above, conventionally, a ticket can be liquidated by using the ticket liquidation machine 60, or by taking the ticket to the cashier or the pouch payer.
However, because the tickets fall in the hands of the cashier or the pouch payer, they can be misused. For example, when the cashier or the pouch payer liquidates a ticket, the liquidated ticket remains in their hands and they can intentionally give that ticket to a malicious third party, or due to their carelessness, that ticket can fall in the hands of the malicious third party. The malicious third party can create a forged ticket by the ticket ID printed on the ticket, by manipulating the barcode that represents the ticket ID, and use the forged ticket to make money.
There is a need of a technology that can prevent illegal use of recording media, such as tickets, that can be used instead of cash.